1. Field of the Invention
The invention relates to the field of removal devices. More particularly, the invention relates to the field of removal heads where a flexible layer of material is removed from a mold or other container. By way of further characterization, but not by way of limitation thereto, the invention is a curvilinear removal head which includes a vacuum source to contact one edge of a flexible sheet such that rotation of the removal head peels the flexible material from a mold.
2. Description of the Prior Art
The manufacture and molding of relatively thin, flexible layers of materials such as agarose gels for electrophoresis has traditionally been a manual, time consuming, procedure. Relatively recent automation of this process has reduced the time and personnel required to mold these materials. However, automated procedures present special problems. One of these problems is the removal of the cast gel layer from the mold without damaging the gel layer. In manual systems the removal of the gel layer was done with tweezers or other means to peel or strip the gel layer from the mold. For automated systems it is desirable to have a device which can remove the gel layer from the mold quickly and without any damage to the gel layer.
Prior automated gel casting apparatus, such as that shown in U.S. Pat. No. 3,635,808 issued to F. R. Elevitch on Jan. 18, 1972, emphasized the use of release agents in the molds to prevent the gel from adhering to the mold. In this device the mold is lowered onto a continuous strip of backing material and the agarose gel is injected into the mold. The mold is then tilted to peel it from the cast gel layer. While suited for its intended purpose, this device can result in damage to the gel layer. In addition, this device requires multiple movements of the mold which may not be practical.
Another device, which is shown in U.S. Pat. No. 3,767,560 issued to F. R. Elevitch on Oct. 23, 1973 (a division of the above referenced patent), uses continuous rolling molds. That is, the individual molds are contained on a roll. A continuous layer of backing material with the gel solution thereon is passed below the roll of molds. The gel layers formed thereby are peeled from the molds by the rotating action of the molds in combination with the movement of the backing material on a continuous belt. While suited for its intended purpose, this device does not allow for the flat molding of the gels. That is, the gels are molded on a curved surface which may result in nonuniformity of, and damage to, the gel layer when it is placed on a flat surface.